SEXUAL SELECTION. 215 



plumes, certainly seems to be a polygamist.'" I have been as- 

 sured by Mr. Jenner Weir and by others, that it is somewhat 

 common for three starlings to frequent the same nest; but 

 ■whether this is a case of polygamy or polyandry has not been 

 ascertained. 



The Gallinaceae exhibit almost as strongly marked sexual dif- 

 ferences as birds of paradise or humming-birds, and many of the 

 species are, as is well known, polygamous; others being strictly 

 monogamous. What a contrast is presented between the sexes 

 of the polygamous peacock or pheasant, and the monogamous 

 guinea-fowl or partridge! Many similar cases could be given, 

 as in the grouse tribe, in which the males of the polygamous 

 capercailzie and black-cock differ greatly from the females; whilst 

 the sexes of the monogamous red grouse and ptarmigan differ 

 very little. In the Cursores, except amongst the bustards, few 

 species offer strongly-marked sexual differences, and the great 

 bustard (Otis tarda) is said to be polygamous. With the Gralla- 

 tores, extremely few species differ sexually, but the ruff (Machetes 

 pugnax) affords a marked exception, and this species is believed 

 by Montagu to be a polygamist. Hence it appears that amongst 

 birds there often exists a close relation between polygamy and 

 the development of strongly-marked sexual differences. I asked 

 Mr. Bartlett, of the Zoological Gardens, who has had very large 

 experience with birds, whether the male tragopan (one of the 

 Gallinaceae) was polygamous, and I was struck by his answering, 

 "I do not know, but should think so from his splendid colors." 



It deserves notice that the instinct of pairing with a single fe- 

 male is easily lost under domestication. The wild-duck is strictly 

 monogamus, the domestic-duck highly polygamous. The Rev. 

 W. D. Fox informs me that out of some half-tamed wild-ducks, 

 on a large pond in his neighborhood, so many mallards were shot 

 by the gamekeeper that only one was left for every seven or 

 eight females; yet unusually large broods were reared. The 

 guinea-fowl is strictly monogamous; but Mr. Fox finds that his 

 birds succeed best when he keeps one cock to two or three hens. 

 Canary-birds pair in a state of nature, but the breeders in Eng- 

 land successfully put one male to four or five females. I have 

 noticed these cases, as rendering it probable that wild monog- 

 amous species might readily become either temporarily or per- 

 manently polygamous. 



Too little is known of the habits of reptiles and fishes to en- 



's 'The Ibis,' vol. iii. 1861, p. 133, on the Progne Widow-bird. See 

 also on the Vidua axillaris, ibid. vol. ii. 1S60, p. 211. On the polyg-amy 

 of the Capercailzie and Great Bustard, see L. Lloyd, 'Game Birds of 

 Sweden,' 1867, p. 19, and 182. Montagu and Selby speak of the Black 

 Grouse as polygamous and of the Red Grouse as monogamous. 



